<!DOCTYPE html>
<html>
<head>
<title>CSS选择器</title>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<style type="text/css">
html,
body,
h1,
h2,
h3,
h4,
h5,
h6,
p,
blockquote,
ol,
ul,
li,
img {
    margin: 0;
    padding: 0;
    font-size: 100%;
    font: inherit;
    vertical-align: baseline;
}

html * {
    font-family: "ff-din-web-pro-1", "ff-din-web-pro-2", sans-serif;
    font-size: 16px;
    line-height: 19.2px;
    color-profile: sRGB;
}

body {
    min-width: 32em;
    max-width: 56em;
    margin: 10px auto;
}

p, blockquote p {
    line-height: 1.6;
}

ul, ol {
    margin: 16px 0;
}

ul li, ol li {
    line-height: 1.6;
}

p {
    font-weight: lighter;
    margin: 10px 0;
}

strong {
    font-weight: bold;
}

ol,
ul {
    margin-left: 2em;
}

h1,
h2,
h3,
h4,
h5,
h6 {
    font-weight: lighter;
    text-transform: capitalize;
    margin: 20px 0;
    border-bottom: 1px solid;
    padding-bottom: 6px;
}

h1, h1 > code {
    font-size: 24.624px;
    line-height: 29.548799999999996px;
}

h2, h2 > code {
    font-size: 24.624px;
    line-height: 29.548799999999996px;
}

h3, h3 > code {
    font-size: 23.44px;
    line-height: 28.128px;
}

h4, h4 > code {
    font-size: 22.16px;
    line-height: 26.592px;
}

h5, h5 > code {
    font-size: 22.16px;
    line-height: 26.592px;
}

h6, h6 > code {
    font-size: 22.16px;
    line-height: 26.592px;
}

img {
    margin-bottom: 20px;
}

h1 img,
h2 img,
h3 img,
h4 img,
h5 img,
h6 img,
p img {
    margin-bottom: 0;
}

pre,
code {
    font-family: monospace, Consolas, "Source Code Pro", Arial, sans-serif;
    color: #586e75;
    background-color: #eee8d5;
}

pre {
    white-space: pre-wrap;
    word-wrap: break-word;
    padding: 12px;
    margin-bottom: 20px;
}

code {
    border-radius: 3px;
}

h1 {
    text-transform: uppercase;
    font-weight: bold;
}

h3,
h4,
h5,
h6 {
    border-bottom: none;
}

html * {
    color: #657b83;
}

html body {
    background-color: #fdf6e3;
}

html h1,
html h2,
html h3,
html h4,
html h5,
html h6 {
    color: #586e75;
    border-color: #657b83;
}

html a,
html a:active,
html a:visited {
    color: #586e75;
    text-decoration: none;
    border-bottom: 1px dashed;
    border-radius: 2px;
}

html a:hover {
    background-color: #eee8d5;
}

blockquote a:hover {
    background-color: #fdf6e3;
}

html a,
html a:active,
html a:visited,
html code.url {
    color: #b58900;
}

html h1 {
    color: #b58900;
}

html h2,
html h3,
html h4,
html h5,
html h6 {
    color: #b58900;
}

/* QUOTES
=============================================================================*/
blockquote {
    border-left: 4px solid #b58900;
    padding: 12px;
    background: #eee8d5;
    border-bottom-right-radius: 2px;
}

blockquote code {
    background: #fdf6e3;
}

blockquote > :first-child {
    margin-top: 0;
}

blockquote > :last-child {
    margin-bottom: 0;
}

/* TABLES
=============================================================================*/
table {
    margin: 0 auto;
    border-collapse: collapse;
    width: 100%;
    box-sizing: border-box;
    margin-bottom: 30px;
}

table th, table td {
    border: 1px solid #ccc;
    padding: 6px 13px;
}

table td {
    word-break: break-word;
    line-height: 1.3;
}

table th {
    font-weight: bold;
    text-align: center !important;
    background-color: #eee8d5;
}

table tr {
    border-top: 1px solid #ccc;
    background-color: #fdf6e3;
}

/* IMAGES
=============================================================================*/
img {
    max-width: 100%;
}

p > img {
    display: table;
    margin: 0 auto;
}

p code, li code, td code {
    padding: 1px 3px;
    border-radius: 3px;
}

.cp_embed_wrapper {
    margin: 20px 0;
}

@media screen and (min-width: 980px) and (max-width: 980px) {	
    table thead tr th,
    table thead tr th > code,
    table tbody tr td,
    table tbody tr td > code,
    table tbody tr td > strong {
        font-size: 1.3em;
        line-height: 1.3;
    }

    p, p code,
    p strong, p strong > code,
    blockquote p {
        font-size: 1.3em;
        line-height: 1.6;
    }

    pre > code,
    ul li pre > code,
    ol li pre > code{
		font-size: 1.3em;
        line-height: 1.3;    	
    }	
	

    ul li, ol li,
    ul li > code,
    ol li > code {
        font-size: 1.3em;
		line-height: 1.3;          
    }

    ul {
        margin-left: 3.4em;
    }

    ol {
        margin-left: 3.6em;
    }
}
</style>
<style type="text/css">
.highlight  { background: #ffffff; }
.highlight .c { color: #999988; font-style: italic } /* Comment */
.highlight .err { color: #a61717; background-color: #e3d2d2 } /* Error */
.highlight .k { font-weight: bold } /* Keyword */
.highlight .o { font-weight: bold } /* Operator */
.highlight .cm { color: #999988; font-style: italic } /* Comment.Multiline */
.highlight .cp { color: #999999; font-weight: bold } /* Comment.Preproc */
.highlight .c1 { color: #999988; font-style: italic } /* Comment.Single */
.highlight .cs { color: #999999; font-weight: bold; font-style: italic } /* Comment.Special */
.highlight .gd { color: #000000; background-color: #ffdddd } /* Generic.Deleted */
.highlight .gd .x { color: #000000; background-color: #ffaaaa } /* Generic.Deleted.Specific */
.highlight .ge { font-style: italic } /* Generic.Emph */
.highlight .gr { color: #aa0000 } /* Generic.Error */
.highlight .gh { color: #999999 } /* Generic.Heading */
.highlight .gi { color: #000000; background-color: #ddffdd } /* Generic.Inserted */
.highlight .gi .x { color: #000000; background-color: #aaffaa } /* Generic.Inserted.Specific */
.highlight .go { color: #888888 } /* Generic.Output */
.highlight .gp { color: #555555 } /* Generic.Prompt */
.highlight .gs { font-weight: bold } /* Generic.Strong */
.highlight .gu { color: #aaaaaa } /* Generic.Subheading */
.highlight .gt { color: #aa0000 } /* Generic.Traceback */
.highlight .kc { font-weight: bold } /* Keyword.Constant */
.highlight .kd { font-weight: bold } /* Keyword.Declaration */
.highlight .kp { font-weight: bold } /* Keyword.Pseudo */
.highlight .kr { font-weight: bold } /* Keyword.Reserved */
.highlight .kt { color: #445588; font-weight: bold } /* Keyword.Type */
.highlight .m { color: #009999 } /* Literal.Number */
.highlight .s { color: #d14 } /* Literal.String */
.highlight .na { color: #008080 } /* Name.Attribute */
.highlight .nb { color: #0086B3 } /* Name.Builtin */
.highlight .nc { color: #445588; font-weight: bold } /* Name.Class */
.highlight .no { color: #008080 } /* Name.Constant */
.highlight .ni { color: #800080 } /* Name.Entity */
.highlight .ne { color: #990000; font-weight: bold } /* Name.Exception */
.highlight .nf { color: #990000; font-weight: bold } /* Name.Function */
.highlight .nn { color: #555555 } /* Name.Namespace */
.highlight .nt { color: #000080 } /* Name.Tag */
.highlight .nv { color: #008080 } /* Name.Variable */
.highlight .ow { font-weight: bold } /* Operator.Word */
.highlight .w { color: #bbbbbb } /* Text.Whitespace */
.highlight .mf { color: #009999 } /* Literal.Number.Float */
.highlight .mh { color: #009999 } /* Literal.Number.Hex */
.highlight .mi { color: #009999 } /* Literal.Number.Integer */
.highlight .mo { color: #009999 } /* Literal.Number.Oct */
.highlight .sb { color: #d14 } /* Literal.String.Backtick */
.highlight .sc { color: #d14 } /* Literal.String.Char */
.highlight .sd { color: #d14 } /* Literal.String.Doc */
.highlight .s2 { color: #d14 } /* Literal.String.Double */
.highlight .se { color: #d14 } /* Literal.String.Escape */
.highlight .sh { color: #d14 } /* Literal.String.Heredoc */
.highlight .si { color: #d14 } /* Literal.String.Interpol */
.highlight .sx { color: #d14 } /* Literal.String.Other */
.highlight .sr { color: #009926 } /* Literal.String.Regex */
.highlight .s1 { color: #d14 } /* Literal.String.Single */
.highlight .ss { color: #990073 } /* Literal.String.Symbol */
.highlight .bp { color: #999999 } /* Name.Builtin.Pseudo */
.highlight .vc { color: #008080 } /* Name.Variable.Class */
.highlight .vg { color: #008080 } /* Name.Variable.Global */
.highlight .vi { color: #008080 } /* Name.Variable.Instance */
.highlight .il { color: #009999 } /* Literal.Number.Integer.Long */
.pl-c {
    color: #969896;
}

.pl-c1,.pl-mdh,.pl-mm,.pl-mp,.pl-mr,.pl-s1 .pl-v,.pl-s3,.pl-sc,.pl-sv {
    color: #0086b3;
}

.pl-e,.pl-en {
    color: #795da3;
}

.pl-s1 .pl-s2,.pl-smi,.pl-smp,.pl-stj,.pl-vo,.pl-vpf {
    color: #333;
}

.pl-ent {
    color: #63a35c;
}

.pl-k,.pl-s,.pl-st {
    color: #a71d5d;
}

.pl-pds,.pl-s1,.pl-s1 .pl-pse .pl-s2,.pl-sr,.pl-sr .pl-cce,.pl-sr .pl-sra,.pl-sr .pl-sre,.pl-src,.pl-v {
    color: #df5000;
}

.pl-id {
    color: #b52a1d;
}

.pl-ii {
    background-color: #b52a1d;
    color: #f8f8f8;
}

.pl-sr .pl-cce {
    color: #63a35c;
    font-weight: bold;
}

.pl-ml {
    color: #693a17;
}

.pl-mh,.pl-mh .pl-en,.pl-ms {
    color: #1d3e81;
    font-weight: bold;
}

.pl-mq {
    color: #008080;
}

.pl-mi {
    color: #333;
    font-style: italic;
}

.pl-mb {
    color: #333;
    font-weight: bold;
}

.pl-md,.pl-mdhf {
    background-color: #ffecec;
    color: #bd2c00;
}

.pl-mdht,.pl-mi1 {
    background-color: #eaffea;
    color: #55a532;
}

.pl-mdr {
    color: #795da3;
    font-weight: bold;
}

.pl-mo {
    color: #1d3e81;
}
.task-list {
padding-left:10px;
margin-bottom:0;
}

.task-list li {
    margin-left: 20px;
}

.task-list-item {
list-style-type:none;
padding-left:10px;
}

.task-list-item label {
font-weight:400;
}

.task-list-item.enabled label {
cursor:pointer;
}

.task-list-item+.task-list-item {
margin-top:3px;
}

.task-list-item-checkbox {
display:inline-block;
margin-left:-20px;
margin-right:3px;
vertical-align:1px;
}
</style>
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<meta name="keywords" content="whjin,前端开发文档,html,css,javascript,canvas,jquery,vue.js,http,ajax,git,webpack">
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<body>
<h1 id="css-">CSS选择器</h1>
<ul>
<li>并集：对选择器进行分组，被分组的选择器可以分享相同的声明。用<strong>逗号</strong>将需要分组的选择器开分。<ul>
<li><code>h1,h2,h3,h4,h5,h6{}</code></li></ul>
</li><li>交集：两种属性同属一个元素 <ul>
<li><code>p.name{}</code>、<code>p#id{}</code>、<code>.name1.name2{}</code></li></ul>
</li><li>后代（派生）：根据元素在位置上的关系定义样式，使用<strong>空格</strong>隔开，后代选择器尽量不要超过3个，不必把每个层级都列出，只需要写关键点即可<ul>
<li><code>li strong {}</code></li></ul>
</li><li>子代：只能选择作为某元素的子元素，只选择子代，往后孙子一代不选择<ul>
<li><code>h1 &gt; strong {}</code></li></ul>
</li><li>兄弟和相邻兄弟：选择紧接在另一元素后的，并且二者有相同父元素<ul>
<li><code>h1 + p {}</code></li></ul>
</li><li>属性：对带有指定属性的HTML元素设置样式，权重为10<ul>
<li><strong>属性选择器</strong>：为带有<code>title</code>属性的所有元素设置样式，<code>[title] {}</code></li><li><strong>属性和值选择器</strong>：为<code>title=&quot;name&quot;</code>的所有元素设置样式，<code>[title=name] {}</code></li><li><strong>设置表单的样式</strong>：<code>input[type=&quot;text&quot;] {}</code></li></ul>
</li><li>伪类：<ul>
<li><code>:active</code>：被激活的元素</li><li><code>:focus</code>：有键盘输入焦点的元素</li><li><code>:hover</code>：鼠标悬停</li><li><code>:link</code>：未被访问的链接</li><li><code>:visited</code>：已被访问的链接</li><li><code>:first-child</code>：元素的第一个子元素</li><li><code>:lang</code>：带有指定<code>lang</code>属性的元素</li></ul>
</li><li><p>权重：</p>
<ul>
<li><code>div</code>（1）</li><li><code>class/类选择器</code>（10）</li><li><code>id</code>（100）</li></ul>
</li><li><p>结构选择器（新增伪类（面试题））</p>
<ul>
<li><code>:not</code>：排除 </li><li><code>:nth-child(n)</code>：第几个元素 从1开始设置</li><li><code>:nth-child(2n)</code>：偶数元素 从0开始设置</li><li><code>:nth-child(2n+1)</code>：奇数元素</li><li><code>:nth-of-type(n)</code>：某个元素下同类型的第几个元素</li><li><code>:nth-last-child</code>：倒数第几个元素</li><li><code>:first-child-&gt;:nth-child(1)</code>：</li><li><code>:fisrt-of-type</code>：第一个同级兄弟元素</li><li><code>:last-of-type</code>：最后一个同级兄弟元素</li><li><code>:nth-of-type(n)</code>：第几个同级兄弟元素   </li><li><code>:last-child</code>：最后一个子元素</li><li><code>:only-child</code>：仅有一个子元素</li><li><code>:only-of-type</code>：只有一个同类型的子元素</li><li><code>:empty</code>：空内容</li><li><code>:checked</code>：被选中 主要用在<code>input</code>表单元素</li></ul>
</li><li><p>属性选择器</p>
<ul>
<li><code>E[attr=val]</code>：</li><li><code>E[attr|=val]</code>：只能等于<code>val</code> 或只能以<code>val-</code>开头</li><li><code>E[attr*=val]</code>：包含<code>val</code>字符串</li><li><code>E[attr~=val]</code>：属性值有多个，其中一个是<code>val</code></li><li><code>E[attr^=val]</code>：以<code>val</code>开头</li><li><code>E[attr$=val]</code>：以<code>val</code>结尾</li></ul>
</li><li><p>目标伪类选择器</p>
<ul>
<li><code>:target()</code>：用来匹配URL指向的目标元素（存在URL指向该匹配元素时，样式效果才会生效）</li></ul>
</li><li><p>伪元素：</p>
<ul>
<li><code>:first-line</code>：匹配首行文本，只能用于块级元素</li><li><code>:first-letter</code>：匹配首字符</li><li><code>:before/:after</code>：DOM元素前后插入额外的内容<ul>
<li>遇到伪元素<code>before/after</code>就要加上<code>content=&#39;&#39;</code></li><li><code>display: block;</code>：独占一行</li><li><code>display: inline-block;</code>：不独占一行</li></ul>
</li></ul>
</li></ul>

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